Study On Small Electric Vehicle Battery Pack Thermoelectric Refrigeration

With the rapid development of the automobile industry and the general improvement of people's living standards,automobile production and possession have continued to rise in recent years,and the development of the automobile industry has also brought serious environmental pollution and energy crisis.Under the background of energy conservation and emission reduction,pure electric vehicles are gradually appearing in the public's field of vision.As the power source of pure electric vehicles,the power battery pack directly determines the overall performance of electric vehicles.Temperature is the main factor affecting the performance of the power battery pack.When the power battery pack works in a high temperature environment,the battery itself heats up rapidly,which leads to a decrease in battery life,and may even cause the battery to run out of control and cause a safety accident.Too low an ambient temperature will cause a slow chemical reaction inside the battery and a decrease in capacity.In order to control the temperature of the power battery pack within a reasonable range,it is necessary to design a reasonable battery thermal management system for the electric vehicle battery pack to meet the temperature control requirements of the battery during daily driving.Based on thermoelectric refrigeration,a thermoelectric cooler isdesigned for the battery case.The refrigeration performance of the thermoelectric cooler under different diffuser structure,cooling fan power and coolant flow is analyzed.The optimized thermoelectric cooler was used to study the effect of thermoelectric cooling on the thermal management performance of power batteries.And theoretically analyze the influence of thermoelectric cooling galvanic arm structure on the cooling efficiency of thermoelectric cooler.The research content has certain guiding significance for improving the application of thermoelectric refrigeration in the field of thermal management of power batteries.The specific research contents are as follows:1.Research on improving the refrigeration performance of thermoelectric coolers mainly includes the study of the structure of the diffuser,the research of the power of the cooling fan and the research of the flow rate of the hot end coolant.The experimental study method is used to determine the reasonable structure of the diffuser,the cooling fan power and the coolant flow.The results show that the performance of the thermoelectric cooler reaches the optimal value when the flow of the cooling fan is 6W and the flow rate of the cooling fan is 120L/h.2.Exploring the influence of thermoelectric refrigeration on the thermal management performance of power battery through experimental methods.The influence of thermoelectric refrigeration on the thermal management performance of power battery is very significant.Combinedwith the number of different cooling units,it can fully meet the requirements of temperature control in the battery box.On average,the temperature inside the box can be lowered by 20 ° C.The number of cooling coils of the thermoelectric cooler can be adjusted according to different temperature requirements,and a new type of diffuser can be designed to meet the requirements of different cooling ranges.In a low temperature environment,the temperature inside the tank can be heated by changing the current of the thermoelectric cooler in combination with the temperature controller.The research results show that thermoelectric refrigeration has a very broad application prospect in the field of pure electric vehicle thermal management.3.The performance of the thermoelectric cooler is optimized by theoretical research.Using the theoretical knowledge of thermoelectric refrigeration,the theoretical mathematical model under the maximum cooling capacity and the maximum temperature difference is derived.The main factors affecting the cooling efficiency of single pair galvanic arm are analyzed by using the model.The model of the contact resistance and contact thermal resistance of the galvanic arm on the cooling efficiency is given.The model is used to optimize the thermoelectric cooling thermoelectric structure.The results show that the cooling efficiency of the thermoelectric cooler increases first and then decreases with the increase of the length of the galvanic arm.Combined with the contactresistance of the galvanic arm and the thermal resistance of the contact,the length of the galvanic arm should be much larger than the thickness of the contact layer.The contact resistance and contact resistance will reduce the cooling efficiency.